lt versus le in string comparision

[Len]

Can anyone explain me this:

$char = 'a';

while ($char lt 'z')
{
   print $char;
   $char++;
}

prints as expected the characters (a..y) but if I change lt in le in the while expression:

while ( $char le 'z' )

it prints (a..yz) instead of the expected (a..z)

Originally posted as a Categorized Question.

[Abigail-II]

Consider this:

    my $str = 'y';
    $str ++; print "$str\n"; 
    $str ++; print "$str\n";

This will print

    z
    aa

Now, both z and aa are less or equal to z. It isn't until you reach za that you have a string that isn't less or equal to z.

Abigail